Needles and needle systems are used extensively in a wide variety of procedures that are performed in various fields of medicine, such as cardiology, radiology, urology, interventional pain management, and internal medicine. The use of needles and needle systems in invasive procedures in various medical fields has become routine due, in part, to the ability of needles to pass through most tissues without causing significant destruction to the tissues. Conventional needles have an orifice or a port at the distal tip of the needle. Distal tips of needles are more liable to clog as the tip of the needle is used for penetration of tissue to access the site of treatment. Additionally, there exists a greater chance of leakage of the agent being delivered, using conventional needles. Needles with orifices located along the length of the needle are routinely used for aspiration purposes as well as for delivering anesthesia. Specifically, a variety of needles having side ports are used for delivery of spinal anesthesia. This configuration reduces the chance of the inability to deliver anesthesia due to clogging of the opening at the needle tip.
A very successful embodiment of a needle with an opening at the distal end portion and with a side port is disclosed in U.S. Pat. No. 5,817,074 (“the '074 patent”). The '074 patent discloses a stellate ganglion sympathetic block needle having a side port positioned at a predetermined distance from the opening of the distal tip. The stellate ganglion sympathetic block needle allows for an effective stellate ganglion sympathetic block even if the needle is placed such that the needle distal opening is under the anterior longitudinal ligament, which results in the needle distal opening being constricted, thereby interfering with the injection of the anesthesia. When this interference occurs, the side port of the stellate ganglion sympathetic block needle allows directional injection onto the surface of the anterior longitudinal ligament in order to spread onto the surface of the longus coli muscle toward the stellate ganglion, thereby achieving an effective stellate ganglion sympathetic block. This invention has found wide applicability; however, certain procedures might prefer a needle with a blocked distal tip and only side port(s) for the administration of therapeutic, diagnostic or prophylactic agents while retaining the sharp point of the distal tip to maneuver and penetrate certain tissues to access treatment sites.
Needles with a blocked tip (distal end) and an open side portal are used for procedures such as thoracentesis, which involves inserting the needle through the thoracic cage into the pleural space between the lung and the chest wall to draw off fluid for diagnostic or therapeutic purposes. Thoracentesis needles generally consist of an orifice free, sharp conical end and a circular side hole for draining fluid. However, these needles are pre-made with an enclosed end, making them much more expensive than traditional open-ended beveled needles to manufacture.
Accordingly, it would be desirable to create a neural injection system that is primarily composed of a traditional open-ended needle system, which is common and inexpensive, and retrofit such a needle to provide a sharp-tipped, open side port, closed distal end, neural injection system.